1. Field of the Invention
The present invention concerns adapters and methods to connect a connecting plug of at least one local coil with a connecting socket located at a magnetic resonance imaging system.
2. Description of the Prior Art
Magnetic resonance apparatuses for the purpose of examining especially patients by magnetic resonance imaging are known, for example, from DE10314215B4.
Magnetic resonance systems operate with coils to transmit high frequency pulses for exciting nuclear spins so as to emit magnetic resonance signals and/or receiving the induced magnetic resonance signals. Typically, a magnetic resonance system has a large so-called whole-body coil (BC), which is usually permanently mounted in the apparatus, as well as several small local coils (also called surface coils or LC).
In current MR imaging (also called magnetic resonance tomography), images with high signal-to-noise ratio are usually obtained with so-called local coils (loops).
In the process, the excited nuclei in the coil induce a voltage that is amplified with a low noise preamplifier (LNA) tuned to the MR frequency, and is transmitted to the receiving electronics. In order to improve the signal-to-noise ratio even in the case of high resolution images, so-called high field systems are used. Currently, their basic field strength is at 3 Tesla and higher. Since it is desirable to connect a number of coil elements (loops) to an MR receiving system that is larger than the number of receivers available, a switching matrix (here called a RCCS) is mounted between the receiving channels and the receivers. The switching matrix routes the currently active reception channels to the available receivers. In this way, it is possible to connect a number of coil elements that exceed the number of receivers available, because in a whole-body coverage only the coils that are in the field of view (FoV) or in the homogeneity volume of the basic field magnet have to be read.
Herein, the individual antenna elements are also denoted as coil elements. A “coil” is an antenna that can include one or several coil elements (array coil). A coil is composed of the coil elements (resonators), the preamplifier, additional electronics and wiring, the housing and in most cases a cable and plug by means of which it is connected to the “system.” The “system” is defined as the MR system.
In developing a new generation of MRI scanners, it is advantageous to be able to use also local coils from previous systems for the apparatuses of the new generation.
One way to address this problem is to provide the new apparatus with an interface for the old apparatus. Another known approach is to provide an interface box having a plug with an old interface, a cable and an electronic box with the new interface. In this case, the electronic box rests, for example, on the patient and the box has no fixed position or local transmission coils. If the box is not protected, it is possible that power from the local transmission coil is coupled into the electronics/wiring within the electronic box and, because of the different mechanical position of the electronic box in relation to the transmission coil, this can result in uncontrolled couplings, which can have an effect on the picture quality and can even contribute to defects of other components (preamplifier).
If the box is connected to the system by means of a flexible cable and the box does not rest on the table but, instead, hangs down at the side of the table, components at the box/cable/plug/table can be destroyed when the table is moved into the bore (examination room inside the MRT).